Thumbing

[Sommer]

[The hip] new way to [indicate] you are [texting]. Matter of fact; all the really cool kids now refer to texting as thumbing.

[Lizzy Liz]

Thumbing in Orienteering. The act of placing your thumb next to your current location on the map while running to save time hunting for your position.

[Couch Potatoe]

the short, thick finger on the side of your hand that makes it possible to hold and pick things up easily